Multi-layer inner core assembly and pipe die head

Abstract

The utility model provides a multi-layer inner core assembly and a pipe die head, the multi-layer inner core assembly comprises an inner core rod and a plurality of inner cores, the inner cores are arranged on the inner core rod in a sleeving mode and are provided with first gaps, the inner core rod is provided with a feeding end and a discharging end, and the first gaps form a main runner extending from the feeding end to the discharging end; the inner cores are sequentially connected from the feeding end to the discharging end in an end-to-end mode, the connecting parts are provided with second gaps and form a plurality of secondary runners, and the secondary runners are sequentially converged into the main runner according to the connecting sequence of the inner cores; the main pipe is injected into the main runner from the feeding end, and the secondary pipes are sequentially stacked on the main pipe from the secondary runner to form a multi-layer pipe which is discharged from the discharging end. According to the multi-layer inner core assembly and the multi-layer pipe die head, the inner core rod is sleeved with the inner cores, the main runner and the secondary runner are formed, it is ensured that pipes of different layers can be stably injected and stacked, the multi-layer pipe is efficiently formed, pipes of more layers are formed through fewer inner core assemblies, and the production efficiency and the finished product quality are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of pipe extrusion dies, and in particular to a multi-layer inner core component and a pipe die head. Background Art

[0002] Pipes are the main means of transporting fluids. In addition to single-layer pipes, there are also multi-layer composite pipes on the market. Existing composite pipes are co-extruded and compounded in layers from the outside to the inside, and only the innermost layer is actually in direct contact with the fluid. In order to expand the function of the pipeline, some add a single functional material to the main material of the innermost layer, which limits the scope of use of such single-function pipes; others add two or more functional materials to the main material of the innermost layer.

[0003] During the extrusion production of multi-layer pipes, sometimes there will be different pipe structures, which require corresponding adjustments. For example, during the extrusion production of five-layer pipes, the materials of different layers of pipes may sometimes need to be changed, and the number of layers of pipe extrusion may also need to be changed. Such changes are very complicated and require replacing the main machine and die head, which is time-consuming and labor-intensive, greatly increasing the cost of production. At the same time, some existing multi-layer pipe die heads can only produce multi-layer pipes with a fixed number of layers. If you want to produce multi-layer pipes with different numbers of layers, you need to replace the pipe die head.

[0004] Therefore, it is necessary to design a pipe die head that can realize multi-layer pipe extrusion and can change the material and number of layers of the pipe as needed. Utility Model Content

[0005] Aiming at the problem that the existing multi-layer tube die head in the prior art cannot flexibly change the material and number of layers of the tube, the utility model proposes a multi-layer inner core component and a tube die head to solve the above problem.

[0006] According to the first aspect of the present application, a multi-layer inner core assembly is proposed, comprising an inner core rod and several inner cores, the inner cores being sleeved on the inner core rod and having a first gap, the inner core rod having a feed end and a discharge end, the first gap forming a main flow channel extending from the feed end to the discharge end; the inner cores are connected end to end in sequence from the feed end to the discharge end, and the connected parts have a second gap and form several secondary flow channels, which merge into the main flow channel in sequence according to the connection order of the inner cores; the main pipe material is injected into the main flow channel from the feed end, and the secondary pipe materials are sequentially stacked on the main pipe material from the secondary flow channels to form multi-layer pipes, and are discharged from the discharge end.

[0007] By adopting the above technical solution, the main pipe material is injected into the feed end of the main channel, and the main pipe material flows toward the discharge end. Then, secondary pipes are injected into each secondary flow channel according to the order of inner core connection, so that the secondary pipes are stacked on the main pipe material in sequence, and finally a multi-layer pipe is formed.

[0008] Preferably, the inner core has a fixing portion and a flow-guiding portion, the flow-guiding portion is stepped and shrinks toward the axial direction, and the fixing portion of the rear inner core is sleeved on the flow-guiding portion of the front inner core.

[0009] Further preferably, the fixed parts of the inner cores except the first inner core are provided with secondary feed holes for injecting secondary pipes into the secondary flow channel; the middle surface of the guide part is also provided with an annular material accumulation groove, and the position of the secondary feed hole corresponds to the material accumulation groove.

[0010] By adopting the above technical solution, under the premise of ensuring that the outer diameters of each inner core after sleeve connection remain consistent, the secondary pipe is injected into the secondary flow channel through the secondary feed hole, and the use of the accumulation trough can ensure that the flow rate of the secondary pipe when entering the secondary flow channel remains stable.

[0011] More preferably, the fixing portion of the rear inner core fits against the guide portion at the front end of the feed trough of the front inner core, and forms a second gap with the guide portion at the rear end of the feed trough.

[0012] By adopting the above technical solution, it is ensured that the secondary pipe will not flow toward the connection between the inner cores after entering the material accumulation tank, thereby preventing the secondary pipe from overflowing from the joint.

[0013] Preferably, the inner core rod includes a core rod head located at the feed end, and a rod body extending from the core rod head to the discharge end, the diameter of the core rod head is larger than the diameter of the rod body, and the fixing part of the first inner core is sleeved on the core rod head, and the end of the core rod head away from the rod body extends in a conical shape to the outside of the inner core.

[0014] By adopting the above technical solution, the core rod head with a larger diameter cooperates with the fixing part of the first inner core to prevent the inner core rod from escaping from the guide part of the inner core, which has a certain limiting effect on the displacement of the inner core rod.

[0015] Further preferably, it also includes a discharge core rod located behind the discharge end, the middle diameter of the discharge core rod is larger than the diameter of the two ends, and one end of the discharge core rod is connected to the rod body, and the guide part of the last inner core is sleeved on the front half of the discharge core rod and has a third gap, and the main channel is connected to the third gap and extends to the other end of the discharge core rod.

[0016] By adopting the above technical solution, the structure of the discharge core rod cannot move through the guide part to the feed end, and the structure of the core rod head can limit the left and right movement range of the inner core rod.

[0017] According to the second aspect of the present application, a multi-layer tube die head is proposed, comprising the above-mentioned multi-layer inner core assembly, and also comprising a mold shell, a feed head and a discharge head. The inner wall of the mold shell is fitted onto the multi-layer inner core assembly, and the feed head and the discharge head are arranged at the two ends of the mold shell corresponding to the positions of the feed end and the discharge end respectively. The main feed port and the main discharge port are respectively provided in the center of the feed head and the discharge head. The main feed port and the main discharge port are connected to the main channel at the feed end and the discharge end respectively.

[0018] By adopting the above technical solution, the feed head and discharge head on both sides press and fix the multi-layer core assembly to the inner wall of the mold shell, which ensures the airtightness of the multi-layer tube mold to a certain extent. The corresponding main feed port and main discharge port are used for the injection and discharge of pipes.

[0019] Preferably, a secondary feed flange is inserted into the side surface of the mold shell at a position corresponding to the secondary feed hole, and the central hole of the secondary feed flange is connected to the secondary flow channel through the secondary feed hole.

[0020] By adopting the above technical solution, the plug-in installed secondary feed flange is in a detachable form and is plugged in at the secondary flow channel where the secondary pipe needs to be injected, making the pipe ratio of the formed multi-layer pipe more flexible.

[0021] Preferably, a main flow groove that adapts to the shape of the core rod head is formed on one side of the feed head close to the mold shell, and the edge of the main flow groove is stuck in the inner wall of the fixed part of the first inner core. There is a fourth gap between the main flow groove and the core rod head, and the fourth gap forms a front end flow channel connecting the feed port and the main channel.

[0022] By adopting the above technical solution, the main pipe material first enters the front flow channel for a certain amount of accumulation before entering the main flow channel, so that the main pipe material can have a stable flow rate when entering the main flow channel from the front flow channel.

[0023] Preferably, the mold shell includes a main shell and a sub-shell. The sub-shell is mounted on the guide portion of the last inner core and also has a secondary flow channel. The rear half of the discharge core rod is gap-matched with the inner wall of the main discharge port, and the main discharge port is connected to the main channel to form a rear end flow channel.

[0024] By adopting the above technical solution, the mold shell is divided into two parts, so that the guide part of the last inner core can also cooperate with the sub-shell to form a secondary flow channel, making full use of the number and structure of the inner cores, and using fewer inner cores to form more layers of multi-layer pipes.

[0025] The multi-layer inner core assembly and multi-layer tube die head of the present application realize efficient and stable multi-layer tube production. The design ensures that tubes of different layers can be stably injected and stacked by arranging several inner cores on the inner core rod and forming main flow channels and secondary flow channels, thereby efficiently forming multi-layer tubes. The accumulation trough and secondary feed hole ensure the stability of the flow and prevent leakage and overflow. The structure of the mold shell and the feed head and discharge head ensures the airtightness and fixation of the components. The plug-in secondary feed flange improves the flexibility of production. The design of the core rod head and the discharge core rod effectively limits the displacement of the inner core rod, ensures the consistency and stability of the structure, and uses fewer inner core components to form more layers of tubes, thereby improving production efficiency and finished product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and, together with the description, serve to explain the principles of the present invention. Other embodiments and many of the expected advantages of the embodiments will be readily apparent as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with respect to each other. Like reference numerals designate corresponding similar parts.

[0027] Figure 1 is a schematic structural diagram of a multi-layer inner core assembly according to an embodiment of the present application;

[0028] Figure 2 is a quarter cross-sectional view of a multi-layer inner core assembly according to an embodiment of the present application;

[0029] Figure 3 is a schematic diagram of a single inner core structure according to an embodiment of the present application;

[0030] Figure 4 is a schematic structural diagram of a multi-layer tube mold according to an embodiment of the present application;

[0031] Figure 5 is a quarter cross-sectional view of a multi-layer tube mold according to an embodiment of the present application;

[0032] Figure 6 It is a partial cross-sectional schematic diagram of a 6-layer and 7-layer pipe according to an embodiment of the present application.

[0033] The meaning of the numbers in the figure:

[0034] Inner core rod 01, inner core 02, first gap 03, main flow channel 04, second gap 05, secondary flow channel 06, fixing part 07, guide part 08, secondary feed hole 09, accumulation trough 10, core rod head 11, rod body 12, discharge core rod 13, third gap 14, mold shell 15, feed head 16, discharge head 17, main feed port 18, main discharge port 19, secondary feed flange 20, main accumulation trough 21, fourth gap 22, front end flow channel 23, main shell 24, auxiliary shell 25, rear end flow channel 26, main pipe 27, secondary pipe 28. DETAILED DESCRIPTION

[0035] In the following detailed description, reference is made to the accompanying drawings, which form a part of the detailed description and are shown by way of illustrative specific embodiments in which the present invention may be practiced. In this regard, directional terms, such as "top," "bottom," "left," "right," "up," "down," etc., are used with reference to the orientation of the figures being described. Because the components of the embodiments may be positioned in several different orientations, directional terms are used for illustrative purposes and are in no way limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the present invention. The following detailed description should therefore not be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0036] According to a first aspect of the present application, a multi-layer core assembly is provided. Figure 1 shows a schematic structural diagram of a multi-layer inner core assembly according to an embodiment of the present application, Figure 2 A quarter cross-sectional view of a multi-layer core assembly according to an embodiment of the present application is shown. Figure 1-2 As shown, the multi-layer inner core assembly includes an inner core rod 01 and several inner cores 02. The inner core 02 is sleeved on the inner core rod 01 and has a first gap 03. The inner core rod 01 has a feed end and a discharge end. The first gap 03 forms a main flow channel 04 extending from the feed end to the discharge end; each inner core 02 is connected end to end from the feed end to the discharge end, and the connected parts have a second gap 05 and form several secondary flow channels 06. The secondary flow channels 06 are sequentially merged into the main flow channel 04 in the order of connection of the inner cores 02; the main pipe 27 is injected into the main flow channel 04 from the feed end, and the secondary pipes 28 are sequentially stacked on the main pipe 27 from the secondary flow channel 06 to form multi-layer pipes, and are extruded from the discharge end.

[0037] Specifically, as shown in the figure, the feed end and the discharge end of the inner core rod 01 are respectively the left end and the right end in the figure, and the first gap 03 between each inner core 02 and the inner core rod 01 is connected from the feed end to the discharge end, forming a main flow channel 04 running through the left and right, and the second gap 05 at the connection between each inner core 02 extends to the right end in a stepped manner to form a secondary flow channel 06, and each secondary flow channel 06 merges into the main flow channel 04 according to the connection order of the inner core 02, and the cross-sections at any position of the main flow channel 04 and the secondary flow channel 06 are annular channels set around the inner core rod 01.

[0038] By adopting the above technical solution, the main pipe material 27 is injected into the left end of the main channel 04, and the main pipe material 27 flows toward the right end. Then, the secondary pipe material 28 is injected into each secondary channel 06 in order from left to right. Specifically, the secondary channel 06 between the second inner core 02 and the first inner core 02 is the first secondary channel 06. The secondary pipe material 28 of the secondary channel 06 is first stacked on the main pipe material 27 and flows to the right end with the main pipe material 27 to the next secondary channel 06. The stacking is carried out in this way to finally form a multi-layer pipe. By changing the composition, proportion and material stacking order of the main pipe material 27 and each secondary pipe material 28 as needed, the material composition of the finally formed multi-layer pipe can be changed, making the multi-layer pipe customizable. At the same time, the length of the inner core rod 01 and the number of inner cores 02 can be set as needed, according to the number of layers of the multi-layer pipe to be formed.

[0039] Figure 3 A schematic diagram of a single inner core structure according to an embodiment of the present application is shown. Figure 1-3 As shown, the inner core 02 has a fixing portion 07 and a flow-guiding portion 08 . The flow-guiding portion 08 shrinks in a stepped manner toward the axial direction, and the fixing portion 07 of the subsequent inner core 02 is sleeved on the flow-guiding portion 08 of the previous inner core 02 .

[0040] Preferably, the fixing portion 07 of the remaining inner cores 02 except the first inner core 02 is provided with a secondary feed hole 09 for injecting the secondary pipe 28 into the secondary flow channel 06; the middle surface of the guide portion 08 is also provided with an annular material accumulation groove 10, and the position of the secondary feed hole 09 corresponds to the material accumulation groove 10.

[0041] Further preferably, the fixing portion 07 of the rear inner core 02 fits against the guide portion 08 at the front end of the material accumulation trough 10 of the previous inner core 02, and forms a second gap 05 with the guide portion 08 at the rear end of the material accumulation trough 10, to ensure that the secondary pipe 28 will not flow toward the connection between the inner cores 02 after entering the material accumulation trough 10, thereby preventing the secondary pipe 28 from overflowing from the joint.

[0042] Specifically, taking the combination of the first inner core 02 and the second inner core 02 as an example, the position of the secondary feed hole 09 of the second inner core 02 can be any point on the circumference of the material accumulation groove 10 on the first inner core 02. The position of the secondary feed hole 09 can be set according to actual conditions. In the figure, the secondary feed holes 09 of adjacent inner cores 02 are staggered at 90°.

[0043] Furthermore, the guide portion 08 of the first inner core 02 is divided into two parts, front and back, with the material accumulation groove 10 as the dividing line. The front half is completely fitted with the fixed portion 07 of the second inner core 02, and the rear half has a second gap 05 with the fixed portion 07 of the second inner core 02. The matching structures of each inner core 02 after the second inner core 02 are similar.

[0044] Furthermore, the secondary pipe 28 first enters the accumulator tank 10 from the secondary feed hole 09 and fully fills the accumulator tank 10, so that the secondary pipe 28 can have a larger and more stable flow rate when entering the secondary flow channel 06 from the accumulator tank 10.

[0045] Preferably, the inner core rod 01 includes a core rod head 11 located at the feed end, and a rod body 12 extending from the core rod head 11 to the discharge end, the diameter of the core rod head 11 is larger than the diameter of the rod body 12, and the fixing part 07 of the first inner core 02 is sleeved on the core rod head 11, and the end of the core rod head 11 away from the rod body 12 extends in a conical shape to the outside of the inner core 02.

[0046] Specifically, when all inner cores 02 are sleeved on the inner core rod 01, the size of the core rod head 11 is larger than the inner wall size of the guide part 08 of the first inner core 02, and the guide part 08 can clamp the core rod head 11 to prevent the inner core rod 01 from falling out from the right end.

[0047] Furthermore, the conical core rod head 11 creates a larger gap between the left end of the fixing portion 07 of the first inner core 02 and the inner core rod 01 , which enables a larger initial flow rate of the main pipe material 27 when entering the main channel 04 .

[0048] Further preferably, it also includes a discharge core rod 13 located behind the discharge end, the middle diameter of the discharge core rod 13 is larger than the diameter of the two ends, and one end of the discharge core rod 13 is connected to the rod body 12, and the guide part 08 of the last inner core 02 is sleeved on the front half of the discharge core rod 13 and has a third gap 14, and the main channel 04 is connected to the third gap 14 and extends to the other end of the discharge core rod 13.

[0049] Specifically, the left end of the discharge core rod 13 is connected to the right end of the rod body 12. Corresponding to the position where the two are connected, the inner diameter of the guide part 08 of the last inner core 02 is smaller than the diameter of the middle part of the discharge core rod 13 at this position, that is, the discharge core rod 13 cannot pass through the guide part 08 and move to the left. The structure of the core rod head 11 can limit the left and right movement range of the inner core rod 01.

[0050] According to a second aspect of the present application, a multi-layer tube mold is proposed. Figure 4 FIG. 1 shows a schematic structural diagram of a multilayer tube mold according to an embodiment of the present application. Figure 5 A quarter cross-sectional view of a multilayer tube mold according to an embodiment of the present application is shown. Figure 1-5 As shown, it includes the above-mentioned multi-layer inner core component, and also includes a mold shell 15, a feed head 16 and a discharge head 17. The inner wall of the mold shell 15 is fitted on the multi-layer inner core 02 component, and the feed head 16 and the discharge head 17 are respectively arranged at the left and right ends of the mold shell 15 corresponding to the positions of the feed end and the discharge end. The center of the feed head 16 and the discharge head 17 are respectively provided with a main feed port 18 and a main discharge port 19. The main feed port 18 and the main discharge port 19 are respectively connected to the main channel 04 at the feed end and the discharge end.

[0051] Specifically, the feed head 16 is designed as a double-layer flange structure, and the middle of the outer flange passes through the center of the inner flange, and is fixed to the left end of the mold shell 15 after passing through the two flanges in sequence through locking parts such as countersunk bolts.

[0052] Preferably, a secondary feed flange 20 is inserted into the side surface of the mold shell 15 at a position corresponding to the secondary feed hole 09 , and a central hole of the secondary feed flange 20 is connected to the secondary flow channel 06 through the secondary feed hole 09 .

[0053] Specifically, the secondary feed flange 20 is inserted into the slots on the mold shell 15 in sequence and docked with each secondary feed hole 09. The secondary pipe 28 is injected into each secondary feed hole 09 through the secondary feed flange 20. The plug-in installed secondary feed flange 20 is in a detachable form and is plugged in at the secondary flow channel 06 where the secondary pipe 28 needs to be injected, so that the pipe ratio of the molded multi-layer pipe is more flexible.

[0054] Preferably, a main flow groove 21 that adapts to the shape of the core rod head 11 is formed on one side of the feed head 16 close to the mold shell 15, and the edge of the main flow groove 21 is stuck in the inner wall of the fixed part 07 of the first inner core 02. There is a fourth gap 22 between the main flow groove 21 and the core rod head 11, and the fourth gap 22 forms a front end flow channel 23 connecting the feed port and the main channel 04.

[0055] Specifically, the main flow groove 21 is a conical groove that fits the core rod head 11, and the main feed port 18 is connected to the top of the conical groove. When the edge of the conical groove is stuck in the inner wall of the first inner core 02, the space between the two is closed and forms a fourth gap 22. The fourth gap 22 connects the main feed port 18 and the main channel 04, forming a conical ring-shaped front end flow channel 23.

[0056] Specifically, a flange is also provided on the outer side of the discharge head 17 , and the flange cooperates with the mold shell 15 to press and fix the discharge head 17 to the right end of the mold shell 15 .

[0057] Preferably, the mold shell 15 includes a main shell 24 and a sub-shell 25. The sub-shell 25 is mounted on the guide portion 08 of the last inner core 02 and also has a secondary flow channel 06. The rear half of the discharge core rod 13 is fitted with the inner wall gap of the main discharge port 19. The main discharge port 19 is connected to the main channel 04 to form a rear end flow channel 26.

[0058] Specifically, the material accumulation trough 10 corresponding to the last inner core 02 on the auxiliary shell 25 is also connected with a secondary feed flange 20, and there is also a gap between the inner wall of the auxiliary shell 25 and the rear half of the guide part 08 of the inner core 02. The gap forms a secondary flow channel 06. The secondary pipe 28 here serves as the last layer, and is superimposed on the multi-layer pipes of the main channel 04 through the secondary flow channel 06, and is discharged from the rear end flow channel 26 to the main discharge port 19.

[0059] Specifically, the outer surfaces of both ends of the main shell 24 are partially cut, and the two ends cooperate with the feed head 16 and the auxiliary shell 25 to form grooves that cooperate with the external bracket (not shown in the figure), so as to ensure the stability of the multi-layer tube die head during operation.

[0060] Figure 6 Schematic diagram of a partial cross section of a 6-layer and 7-layer pipe according to an embodiment of the present application is shown, as shown in FIG. Figure 1-6 As shown in the figure, the leftmost layer is the main pipe material 27, and the rest are secondary pipe materials 28 stacked on the main pipe material 27 in sequence. By changing the material of the secondary pipe material 28, multi-layer pipes with different components can be formed.

[0061] In the present application, four secondary feed flanges 20 are plugged into the main shell 24, and one secondary feed flange 20 is plugged into the auxiliary shell 25, forming five secondary flow channels 06, which are superimposed on the main channel 04 and can form six layers of pipes. In actual application, five secondary feed flanges 20 can be set on the main shell 24. By extending the length of the inner core rod 01 and the main shell 24, and increasing the number of inner cores 02, seven layers of pipes can be formed. At the same time, the auxiliary shell 25 can also be operated in sequence to increase the number of secondary flow channels 06 to achieve the formation of more layers of pipes, not limited to the six and seven layers of pipes mentioned above; at the same time, by changing the size of the inner core 02 and the inner core rod 01, the area of ​​the main channel 04 and the secondary flow channel 06 can be changed. Inner cores 02 and inner core rods 01 of different sizes can be matched to form multi-layer pipes of different thicknesses. During production, the material type of each layer of pipe is selected according to the usage so that the formed multi-layer pipe can be suitable for different usage scenarios.

[0062] The multi-layer inner core 02 assembly and multi-layer tube die head of the present application achieve efficient and stable multi-layer tube production. This design ensures that different layers of tubes can be stably injected and stacked by sleeved multiple inner cores 02 on the inner core rod 01, forming a main channel 04 and a secondary channel 06, thereby efficiently forming multi-layer tubes. The accumulation trough 10 and the secondary feed hole 09 ensure stable flow and prevent leakage and overflow. The structure of the mold shell 15 and the feed head 16 and discharge head 17 ensures airtightness and assembly fixation. The plug-in secondary feed flange 20 improves production flexibility. The design of the core rod head 11 and the discharge core rod 13 effectively limits the displacement of the inner core rod 01, ensuring structural consistency and stability. Using fewer inner cores 02, more layers of tubes can be formed, improving production efficiency and finished product quality.

[0063] Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and changes are within the scope of the claims of the present invention and their equivalents, the present invention is also intended to cover these modifications and changes. The word "comprising" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that the combination of these measures cannot be used to advantage. Any reference signs in the claims should not be considered as limiting the scope.

Claims

1. A multi-layer inner core component, characterized in that: It includes an inner core rod and several inner cores, the inner core is sleeved on the inner core rod and has a first gap, the inner core rod has a feed end and a discharge end, the first gap forms a main flow channel extending from the feed end to the discharge end; each inner core is connected end to end from the feed end to the discharge end, and the connected parts have a second gap and form several secondary flow channels, the secondary flow channels are sequentially merged into the main flow channel in the order of connection of the inner cores; the main pipe is injected into the main flow channel from the feed end, and the secondary pipes are sequentially superimposed on the main pipe from the secondary flow channels to form multi-layer pipes, and are extruded from the discharge end.

2. The multi-layer inner core component according to claim 1, characterized in that The inner core comprises a fixing portion and a flow-guiding portion, wherein the flow-guiding portion is stepped and shrinks toward the axial direction, and the fixing portion of the rear inner core is sleeved on the flow-guiding portion of the front inner core.

3. The multi-layer inner core component according to claim 2, characterized in that The fixed parts of the inner cores except the first one are all provided with secondary feed holes for injecting the secondary pipe into the secondary flow channel; the middle surface of the guide part is also provided with an annular material accumulation groove, and the position of the secondary feed hole corresponds to the material accumulation groove.

4. The multi-layer inner core assembly according to claim 3, characterized in that The fixing portion of the latter inner core fits with the guide portion at the front end of the material accumulation trough of the former inner core, and forms the second gap with the guide portion at the rear end of the material accumulation trough.

5. The multi-layer inner core assembly according to claim 1, characterized in that The inner core rod includes a core rod head located at the feed end and a rod body extending from the core rod head to the discharge end. The diameter of the core rod head is larger than the diameter of the rod body, and the fixing part of the first inner core is sleeved on the core rod head. The end of the core rod head away from the rod body extends in a conical shape to the outside of the inner core.

6. The multi-layer inner core assembly according to claim 5, characterized in that It also includes a discharge core rod located behind the discharge end, the middle diameter of the discharge core rod is larger than the diameters of the two ends, and one end of the discharge core rod is connected to the rod body, and the guide portion of the last inner core is sleeved on the front half of the discharge core rod and has a third gap, and the main channel is connected to the third gap and extends to the other end of the discharge core rod.

7. A multi-layer tube die head, comprising the multi-layer inner core assembly according to any one of claims 1 to 6, characterized in that: It also includes a mold shell, a feed head and a discharge head. The inner wall of the mold shell is fitted onto the multi-layer inner core component. The feed head and the discharge head are respectively arranged at the two ends of the mold shell corresponding to the positions of the feed end and the discharge end. The centers of the feed head and the discharge head are respectively provided with a main feed port and a main discharge port. The main feed port and the main discharge port are respectively connected to the main channel at the feed end and the discharge end.

8. The multi-layer tube die head according to claim 7, characterized in that: A secondary feed flange is inserted into the side surface of the mold shell at a position corresponding to the secondary feed hole, and a central hole of the secondary feed flange is communicated with the secondary flow channel through the secondary feed hole.

9. The multi-layer tube die head according to claim 7, characterized in that: A main flow accumulation groove adapted to the shape of the core rod head is formed on one side of the feed head close to the mold shell, and the edge of the main flow accumulation groove is stuck in the inner wall of the fixed part of the first inner core. There is a fourth gap between the main flow accumulation groove and the core rod head, and the fourth gap forms a front end flow channel connecting the feed port and the main channel.

10. The multi-layer tube die head according to claim 7, characterized in that: The mold shell includes a main shell and a sub-shell. The sub-shell is mounted on the guide portion of the last inner core and also has the secondary flow channel. The rear half of the discharge core rod is gap-matched with the inner wall of the main discharge port, and the main discharge port is connected to the main flow channel to form a rear end flow channel.

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